In short: 0402, 0603, 0805 and 1206 are imperial codes for chip bodies of 1.0×0.5, 1.6×0.8, 2.0×1.25 and 3.2×1.6 mm; each step up gives bigger pads, more power rating and easier hand soldering, while each step down saves board area but demands tighter placement accuracy and stencil control.
Two naming systems, one dangerous trap
Passive chip components are named by body length and width. The imperial code is in hundredths of an inch, so 0603 means 0.06 in × 0.03 in. The metric code is in tenths of a millimetre, so the same part is 1608 (1.6 × 0.8 mm). Datasheets from Japanese and European vendors often print the metric code, while most Western BOMs use imperial.
Key fact: metric 0603 is a completely different part from imperial 0603. Metric 0603 is 0.6 × 0.3 mm, which is the imperial 0201. Mixing the two on a purchase order is a classic way to receive a reel your feeders cannot even hold.
So always write the code with its system, for example "0603 (1608M)", in your BOM header. If you are new to how these parts fit into the wider component family, start with our overview of what a PCB is and then look at the package families on the board.
Sizes at a glance
| Imperial | Metric | Body L × W (mm) | Typical resistor rating | Approx. pad centre-to-centre |
|---|---|---|---|---|
| 0402 | 1005 | 1.0 × 0.5 | 1/16 W (0.063 W) | about 1.0 mm |
| 0603 | 1608 | 1.6 × 0.8 | 1/10 W (0.1 W) | about 1.6 mm |
| 0805 | 2012 | 2.0 × 1.25 | 1/8 W (0.125 W) | about 2.0 mm |
| 1206 | 3216 | 3.2 × 1.6 | 1/4 W (0.25 W) | about 3.0 mm |
The pad spacing column is indicative only. Actual numbers depend on the IPC-7351 density level and on your fabricator's capability, so always take the final pattern from a verified library.
From body size to land pattern
A land pattern is the copper footprint that the solder joint forms on. IPC-7351 builds it from the worst-case component dimensions plus three fillet allowances: a toe fillet beyond the termination, a heel fillet under it, and a side fillet. The result is a pad that extends a little beyond the termination on the outside, which gives the solder meniscus somewhere to form and lets an inspector see a wetted joint.
Three IPC density levels exist. Level A (most) gives the largest pads for hand work and rework, level B (nominal) is the default for production, and level C (least) is for dense boards. Choosing level C on a 1206 is pointless; choosing level A on an 0402 can leave pads so close that solder bridges under the part.
Two geometry details matter more than people expect. First, the gap between pads must be wide enough to keep solder paste from joining under the body. Second, both pads must be the same size and must see the same copper. If one pad connects to a large plane without a thermal relief, it acts as a heat sink, the other pad melts first, and surface tension lifts the part upright. That defect is called tombstoning, and it hits small parts like 0402 and 0201 far more often than 1206.
What the pick-and-place machine sees
Placement machines are rated by the smallest part they can handle reliably and by the accuracy they hold at a given speed. A well-tuned chip shooter handles 0402 comfortably; 0201 needs finer nozzles, higher-resolution vision and tighter stencil control; 01005 is a specialist line. For 0805 and 1206 almost any machine works, so these sizes are common on low-volume, mixed-technology and high-voltage boards.
Practical constraints scale with size:
- Nozzle and feeder: 0402 needs a small-bore nozzle and an 2 mm pitch tape pocket; 1206 uses a standard nozzle and 4 mm tape.
- Placement tolerance: a 0.1 mm shift is 20% of an 0402 body width but only 6% of a 1206, so small parts self-centre less forgivingly.
- Stencil: a 0402 aperture of about 0.45 mm wide with a 100 µm foil works, but the area ratio (aperture area divided by wall area) must stay above roughly 0.66 for clean paste release.
- Spacing: assembly houses publish minimum courtyard-to-courtyard rules, commonly 0.2 to 0.3 mm for small passives.
Hand solderability, from 1206 down to 0402
For prototyping and rework, size is the whole story. 1206 and 0805 can be held with ordinary tweezers and soldered with a 1.5 mm chisel tip. 0603 is the sweet spot for hobby and lab boards: still visible without magnification, but small enough to save real area. 0402 needs a fine conical tip, good flux, a microscope or at least 3x magnification, and a steady hand. Below that, hot-air with paste is the only sane method.
Key fact: a typical lab-friendly rule is 0603 minimum for hand-built prototypes, 0402 only when density forces it, and 0805 or 1206 wherever the part carries real power or voltage.
Electrical limits also push you towards bigger sizes. Power dissipation follows the body area, voltage rating follows the termination spacing, and ceramic capacitors lose effective capacitance under DC bias faster in smaller cases. A 10 µF capacitor in 0402 can behave like 3 µF at its working voltage, so check the manufacturer's DC-bias curve, not the nominal value. When a part must carry current, see how copper width scales in our guide to trace width and current capacity.
Choosing a size in practice
- Dense phone-class or wearable board: 0402 or 0201 for decoupling, with a fabricator that quotes 100 µm stencils.
- General embedded design: 0603 for resistors and small capacitors; it balances yield and area.
- Power stages, LED drivers, mains-adjacent circuits: 0805 or 1206 for wattage and creepage.
- High-speed nets: smaller parasitics favour 0402, and pad shape affects the impedance discontinuity, so review the channel using signal integrity principles.
EDA tools help here. Altium, Cadence Allegro and Siemens Xpedition libraries are normally generated from IPC-7351 calculators, and design-rule checks can enforce minimum pad-to-pad and courtyard spacing. Whichever tool you use, run the fabricator's DFM report before release, because an assembly house knows its own machine better than any library does. If the layer count is also being decided, compare single and multilayer boards, since stack-up changes how many small parts you can route around.
Teams that want this designed rather than learned can look at the board-design services at Avecas, which covers library creation, DFM review and layout for production boards.
Ready to go from reading footprints to laying out full boards? Explore the hands-on PCB tracks in our CourseTron courses.
Frequently asked questions
Is 0603 the same as 1608?
Yes, if 0603 is the imperial code. Imperial 0603 equals metric 1608 (1.6 × 0.8 mm). Metric 0603 is a far smaller 0.6 × 0.3 mm part, equal to imperial 0201.
Can I use an 0805 footprint for a 0603 part?
You can sometimes fit a smaller body on a larger pad, but the larger gap and pad area raise the risk of tombstoning and poor fillets. Use the correct footprint, or a purpose-made combined footprint that your assembler has approved.
Which size is easiest to hand solder?
1206 is the easiest, followed by 0805. 0603 is still workable without magnification, while 0402 needs magnification and a fine tip.
Why do smaller parts tombstone more?
Surface tension and thermal imbalance act on a very small mass. If one pad wets before the other, the pull is enough to stand the part up. Equal pads, balanced copper and a well-tuned reflow profile reduce it.